1. Field of the Invention
This invention relates to an exposure apparatus for use in an electrophotography printer, a digital PPC, or a facsimile, etc.
2. Description of the Related Art
An exposure apparatus of this type is disclosed in Published Unexamined Japanese Utility Model Application No. 55-168961.
This apparatus employs an anode substrate which has anodes arranged in a dotted line or dotted lines, and a fluorescent layer formed thereon. Further, there are provided in the apparatus direct heated cathodes above the anode substrate, control electrodes between the cathodes and the anode substrate, and an optical plate having a line or lines of light transmitting fibers buried therein.
In this structure, electrons are discharged from the cathodes onto the fluorescent layer of the anode substrate at the time of exposure, to thereby cause light to be emitted from the fluorescent layer. The emitted light is transmitted through the fibers onto a photosensitive member, forming a latent image thereon.
This exposure apparatus has been used generally in a printer which operates at relatively low speed and has a relatively low resolving power, since it has a structure which is not suitable for increasing its resolving power and brightness.
Specifically, light emitted from the fluorescent member serving as a light emitting element cannot efficiently be utilized in the exposure apparatus, since the light transmitting fibers employed, such as a lens array consisting of light-converging fibers, are separated by some distance from the fluorescent member.
Thus, in order to brighten the light emitting element by use of the lens array, the light emission area of the element must be enlarged. In other words, the resolving power of the printer must be kept low in order to speed up the operation of the same.
On the other hand, in order to enhance the resolving power, the light emission area must be reduced. Reducing the light emission area causes a proportional reduction in the brightness of the same. In order to avoid this, the speed of the operation of the printer must be reduced.